A generic vessel for storing a fuel and/or operating medium is known from EP 1 502 794 A2.
For the operation in particular of utility vehicles operated with diesel fuel, urea or AdBlue is used for the reduction of soot. Here, the urea is generally carried on-board in a separate tank.
To prevent instances of erroneous tank filling in which the tank provided for the fuels is filled with urea, it is conventional for the pump nozzle to be provided with a special closing mechanism. For the actuation of the closing mechanism, the tank provided for urea has, connected to the filler neck, a separate insert piece which bears an annular magnet in its wall. It is the intention here for a pump nozzle which is matched in terms of its shape to the inner shape of the insert piece to be inserted so far into the filler neck and into the insert piece retained therein that the annular magnet surrounds the pump nozzle at a region in which the closing mechanism is arranged in the pump nozzle. The closing mechanism in the pump nozzle is opened up exclusively by the action of the annular magnet. The intention of this is to reliably prevent instances of erroneous tank filling in which fluid tanks not provided with an associated insert piece with an annular magnet are filled with urea.
Conversely, it is sought to prevent erroneous tank filling of urea tanks with fuel by virtue of the insert piece requiring a certain shape of the pump nozzle or of the spout of the pump nozzle, such that pump nozzles for fuel tank filling do not fit into the insert piece provided in urea tanks.
Such a solution is also known from the generic document EP 1 502 794 A2. The tank known from the generic document is formed from plastic. Here, the plastic tank has, in the region of a filling opening, a tank neck with a collar extension. A separate filler neck as a support for a closure cap is fastened to the tank neck. Furthermore, there is mounted on the tank neck an erroneous tank filling insert which bears an annular magnet in its wall. The erroneous tank filling insert is connected to the tank neck by virtue of the erroneous tank fining insert being fastened to a collar piece which serves as a retainer and which is supported with an encircling flange on the upper edge of the tank neck and which projects into the tank neck. Here, the flange is connected via screws to the upper edge of the tank neck. The collar piece to which the erroneous tank filling insert is fastened also serves for fastening the filler neck to the closure cap. Here, the fastening is realized by spot welding.
A disadvantage of EP 1 502 794 A2 is the complicated construction involving a large number of parts, and the resulting high production and assembly outlay.
DE 20 2005 011 575 U1 discloses a filler neck for a vessel composed of plastic for preventing erroneous filling of the vessel. The filler neck can be closed off by a closure cap. It is the intention for a plastic holder for a permanent magnet to be inserted into the filler neck. It is provided here that the plastic holder which receives the permanent magnet is directly connected in a liquid-tight fashion to the filler neck. It is thereby sought to achieve that only a single component provided with the permanent magnet is arranged in the filler neck, which component as an insert part together with the filler neck allows the permanent magnet to be held in a liquid-tight manner.
Via the solution presented in DE 20 2005 011 575 U1, although the number of components required is reduced in relation to the solution in accordance with EP 1 502 794 A2, there is still a need for a relatively high level of constructional outlay. Furthermore, the filler neck must be mounted on, preferably welded to, a vessel composed of plastic, in a way not described in any more detail in DE 20 2005 011 575 U1.